A communications satellite is an artificial satellite placed into orbit around earth to, among other things, facilitate communications on earth. Communications satellites normally include antenna systems, which typically receive information from and transmit information to various locations on earth.
Phased-array antenna systems, which are well-known, are one type of antenna system that has been used with communications satellites. A phased-array antenna system is comprised of a plurality of antenna elements which are suitably spaced relative to one another. The antenna system generates a radiation pattern having a shape and direction that is determined by the combination of the relative phases and amplitudes of the signals applied to the antenna elements. By varying the relative phases of the signals applied to the antenna elements, the antenna's direction of radiation may be steered.
Conventional phased-array antenna systems typically include a driver stage, a plurality of transmit/receive modules ("T/R modules") and an RF feed network comprised of RF transmission lines. In addition, such antenna systems include a DC power wire harness having a plurality of DC power signal conductors and a digital command/telemetry signal wire harness having a plurality of command/telemetry signal conductors.
Thus, typically, in conventional phased-array antenna systems, each T/R module is electrically connected to the driver stage via (1) an RF transmission line, (2) a DC power signal conductor from the DC power wire harness and (3) a command/telemetry signal conductor from the digital command/telemetry signal wire harness. Both the DC power signal conductors and the command/telemetry signal conductors are typically several meters (or more) in length and require shielding, sheathing, connectors and connector back shells. Furthermore, both the DC power wire harness and the digital command/telemetry signal wire harness require mounting hardware. Thus, when a phased-array antenna system includes hundreds or more TIR modules, the complexity and weight of the system increases dramatically due to the presence of the DC power wire harness, digital command/telemetry signal wire harness and their respective conductors.
When communications satellites are deployed into space, costs associated with delivering spacecraft payloads into the earth's orbit are based on the payload's weight. Thus, there is a need to reduce the weight of antenna systems associated with communications satellites. In addition, because antenna deployment is one of the highest risk components of a space-based satellite mission, there is a need to reduce antenna deployment risks. Finally, there is a need to reduce antenna costs, including costs related to procurement, testing and installation.